Conventionally, as a blower of this type, there has been known a blower in which an orifice having a bellmouth-shaped inflow port is formed (see PTL 1, for example).
Hereinafter, the conventional blower is described with reference to FIG. 6.
As shown in FIG. 6, in centrifugal multi-blade fan 102 of multi-blade blower 101, a plurality of blades 108 are annularly formed on a portion of bottom plate 107 in the vicinity of an outer peripheral edge of bottom plate 107 in the circumferential direction. Annular holder ring 109 is formed on top portions of blades 108 on a side opposite to bottom plate 107. Ceiling portion 105 of casing 104 which houses centrifugal multi-blade fan 102 is positioned higher than a top portion of centrifugal multi-blade fan 102, and bellmouth 110 which is raised from ceiling portion 105 is formed. Bellmouth 110 is bent in a semi-arcuate shape, and an inner diameter end of bellmouth 110 extends downwardly to an area in the vicinity of the top portion of centrifugal multi-blade fan 102. Bellmouth 110 is provided for preventing the generation of a reverse flow of air toward an inner diameter, the air passing a minute gap formed between lower end 106 of the bellmouth and fan top portion 103 through an area in the vicinity of ceiling portion 105 of casing 104 from an outer periphery of centrifugal multi-blade fan 102 which is a blow-out port of blades 108.